The present invention relates generally to fluid level gauges or monitors, and particularly to a fluid level gauge or monitor for use with water or fuel wells, and the like.
In many localities, water is supplied to consumers by pumping the water from wells. Water wells can be quite deep, some reaching depths of over 500 meters. In states or countries which have low amounts of precipitation, well water is a precious commodity, and wells are intensively pumped to meet the consumer demand. In such cases, the level of the water in the well can reach low levels, and the pumped water can become mixed with sand or sea water. It is readily understood that such a situation is undesirable and intolerable. The sand that is pumped with the water can foul and damage irrigation pumps of agricultural consumers. The quality of water mixed with sea water is intolerable and dangerous for drinking purposes. It is thus imperative to monitor the water level in the well, in order to know when to stop pumping water from the well. Unfortunately, the prior art has no known solution for real-time monitoring of water level in a well, especially deep wells.
The present invention seeks to provide a novel fluid level monitor (or gauge, the terms being used interchangeably herein) that can be used for real-time monitoring of water level in a well. Although the present invention is described herein for water wells, nevertheless the invention is applicable for any kind of fluid, such as oil.
The present invention includes a buoyant element that is initially partially submerged at an equilibrium position in a fluid. The buoyant element is suspended from a filament wound on a spool. There is a nominal tensile force in the filament due to the partially submerged weight of the buoyant element. The tension in the filament is sensed by a load sensor. A change in the level of the fluid changes the tensile force in the filament. By comparing the sensed tension to the nominal tension in the filament, the load sensor can sense the direction of the upward or downward movement of the buoyant element. A rotation sensor is provided for sensing the rotation of a spool or bobbin around which the filament is wound. This rotation is interpreted as an amount of distance traveled by the buoyant element. Combined with the force direction as sensed by load sensor, the distance the buoyant element has traveled and in what direction is known. Thus the level of the fluid can be constantly monitored.
A computerized system of fluid level monitors for monitoring a plurality of wells in a locality or state is also provided.
There is thus provided in accordance with a preferred embodiment of the present invention a fluid level monitor including a fluid level monitor including a buoyant element suspended from a filament wound on a spool, a load sensor that senses a tensile force in the filament, and a rotation sensor that senses the rotation of the spool around which the filament is wound, wherein the buoyant element is adapted to be initially at least partially submerged at an equilibrium position at an initial level of a fluid, thereby creating a nominal tensile force in the filament, wherein a change in the level of the fluid changes the tensile force in the filament, a positive change in the tensile force corresponding to a downward movement of the buoyant element and a negative change in the tensile force corresponding to an upward movement of the buoyant element, wherein the rotation of the spool corresponds to an amount of distance traveled by the buoyant element.
In accordance with a preferred embodiment of the present invention the buoyant element is disposed inside a generally vertical elongate tube.
Further in accordance with a preferred embodiment of the present invention at least one friction-reducing member is mounted on an external surface of the buoyant element.
Still further in accordance with a preferred embodiment of the present invention a motor is attached to the spool for rotating the spool so as to raise or lower the buoyant element.
Additionally in accordance with a preferred embodiment of the present invention the filament is also wound about a bobbin, and the bobbin is mounted in a support member that is attached to the load sensor, the load sensor sensing an upward or downward movement of the support member and the buoyant element.
In accordance with a preferred embodiment of the present invention a toothed disc is coaxially mounted with at least one of the spool and the bobbin, and a proximity sensor is mounted in proximity to teeth of the disc.
Further in accordance with a preferred embodiment of the present invention the proximity sensor includes at least one of an induction sensor and a capacitance sensor.
Still further in accordance with a preferred embodiment of the present invention a second proximity sensor is mounted near the filament remote from the spool.
Additionally in accordance with a preferred embodiment of the present invention a controller is in electrical communication with the load sensor and the rotation sensor.
There is also provided in accordance with a preferred embodiment of the present invention a system for monitoring fluid level in wells, including a plurality of the fluid level monitors, and a central processor in communication with the monitors. The monitors may be remotely controlled by a remote controller and/or by the central processor.